Pseudomonas putida metabolizes Phe and Tyr through a peripheral pathway involving hydroxylation of Phe to Tyr (PhhAB), conversion of Tyr into 4-hydroxyphenylpyruvate (TyrB), and formation of homogentisate (Hpd) as the central intermediate. Homogentisate is then catabolized by a central catabolic pathway that involves three enzymes, homogentisate dioxygenase (HmgA), fumarylacetoacetate hydrolase (HmgB), and maleylacetoacetate isomerase (HmgC), finally yielding fumarate and acetoacetate. Whereas the phh, tyr, and hpd genes are not linked in the P. putida genome, the hmgABC genes appear to form a single transcriptional unit. Gel retardation assays and lacZ translational fusion experiments have shown that hmgR encodes a specific repressor that controls the inducible expression of the divergently transcribed hmgABC catabolic genes, and homogentisate is the inducer molecule. Footprinting analysis revealed that HmgR protects a region in the Phmg promoter that spans a 17-bp palindromic motif and an external direct repetition from position ؊16 to position 29 with respect to the transcription start site. The HmgR protein is thus the first IclR-type regulator that acts as a repressor of an aromatic catabolic pathway. We engineered a broad-host-range mobilizable catabolic cassette harboring the hmgABC, hpd, and tyrB genes that allows heterologous bacteria to use Tyr as a unique carbon and energy source. Remarkably, we show here that the catabolism of 3-hydroxyphenylacetate in P. putida U funnels also into the homogentisate central pathway, revealing that the hmg cluster is a key catabolic trait for biodegradation of a small number of aromatic compounds.

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The effects of freezing temperature (−80, −40 or −24 • C) and thawing mode (microwave or overnight at 4 • C) on quality parameters of mashed potatoes made from tubers (cv Kennebec) and from potato flakes were examined, as was the effect of long-term frozen storage on the quality of mashed potatoes. Mashed potatoes were tested for texture profile analysis (TPA) and cone penetration, oscillatory and steady rheometry, colour, dry matter, Brix and sensory analyses. In natural mashed potatoes, TPA hardness and oscillatory parameters showed that processing resulted in a softer product than the fresh control. The parameters were lower in the samples thawed at 4 • C than in those thawed by microwave at all the freezing temperatures used, which may be ascribed to gelatinisation of the starch released from damaged cells. Differences from the freshly prepared product decreased when the samples were frozen at −80 • C and thawed by microwave. No difference was found in sensory acceptability between samples frozen at −80 and −40 • C, which probably reflects the panellists' mixed preferences for air-thawed versus microwave-thawed samples. Increasing the time in frozen storage led to a natural mash with a firmer texture, higher L * /b * value and Brix; nonetheless, panellists found the samples at 0, 3 and 12 months of frozen storage equally acceptable. In commercial mash, penetration and oscillatory parameters showed that processing made for a firmer product than the fresh control, probably owing to retrogradation of gelatinised starch. Thawing mode had a significant effect on parameters, which were lower in the samples thawed at 4 • C. The structure and quality of commercial mash was more detrimentally affected by freezing and, therefore, we would not recommend either freezing or frozen storage of this mashed potato in the used conditions. Natural mash made from Kennebec potatoes should be frozen quickly and thawed by microwave in the conditions described to obtain a product more similar to that freshly made. If the samples are frozen by air blasting at −40 • C, the product can withstand frozen storage for one year.

Pistachio nut contains several protein allergens able to trigger type I hypersensitivity reactions. These allergens can be found also in cashew nut and mango seed but not in mango pulp.

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Most available structures of amyloids correspond to peptide fragments that self-assemble in extended cross β sheets. However, structures in which a whole protein domain acts as building block of an amyloid fiber are scarce, in spite of their relevance to understand amyloidogenesis. Here, we use electron microscopy (EM) and atomic force microscopy (AFM) to analyze the structure of amyloid filaments assembled by RepA-WH1, a winged-helix domain from a DNA replication initiator in bacterial plasmids. RepA-WH1 functions as a cytotoxic bacterial prionoid that recapitulates features of mammalian amyloid proteinopathies. RepA are dimers that monomerize at the origin to initiate replication, and we find that RepA-WH1 reproduces this transition to form amyloids. RepA-WH1 assembles double helical filaments by lateral association of a single-stranded precursor built by monomers. Double filaments then associate in mature fibers. The intracellular and cytotoxic RepA-WH1 aggregates might reproduce the hierarchical assembly of human amyloidogenic proteins.

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2 Abstract Cryoprotectants such as hydrocolloids (amidated low-methoxyl (ALM) and high methoxyl (HM) 1 pectins), kappa-and iota-carrageenans (k-C and i-C), xanthan gum (XG)) and dairy proteins (whey protein (WP), 2 sodium caseinate (SC)) were added to mashed potatoes to investigate ways of improving the effects of freezing 3 and thawing. It was found that each hydrocolloid and protein, depending on concentration, affected the 4 mechanical properties (instrumental textural profile analysis (ITPA), cone penetration (CP) test), the total colour 5 difference (E*) with respect to fresh control (FC) and the sensory attributes of fresh (F) and frozen/thawed 6 (F/T) mashed potatoes in a different way. In the F/T samples, adding 5 and 8 g kg -1 ALM, 3, 5 and 8 g kg -1 k-C, 7 1.5, 3, 5 and 8 g kg -1 i-C and 1.5, 5 and 15 g kg -1 WP significantly increased ITPA consistency. Also, adding 2.5 8 and 5 g kg -1 XG significantly increased ITPA consistency of the F/T product. In both F and F/T samples, k-C 9 provided the highest ITPA consistency and also high CP average force evidencing a stronger synergistic effect in 10 -C/denatured milk protein systems, although the excessive thickening and stickiness provided was judged 11 undesirable by the panellists. Adding 8 g kg -1 HM pectin had a disruptive effect in the mashed potatoes, and 12 decreased both ITPA consistency and CP average force. In all cases, freezing and thawing reinforced the gel 13 structure of the products as compared to F and FC counterparts. The E* values were higher in F samples 14 containing ALM and HM pectins. Dairy proteins affected the taste and odour of the mashed potatoes and were 15 judged unacceptable in the sensory analysis. Samples containing 0.5 and 1.5 g kg -1 added XG were preferred 16 organoleptically due to the creamy mouthfeel it produced. ITPA consistency correlated well with sensory texture 17 attributes. relatively new kind of high-quality product with a good potential market in Europe [3]. However, freezing and 7 thawing of foods can have a detrimental effect on their sensory and water-holding properties as a result of 8 physical disruption of cells or cell components or to changes in the structure of certain macromolecules [4]. 9Technological solutions adopted to minimize the effects of freezing include the use of rapid freezing methods. 10When authors examined the effects of freezing temperature (-80 °C, -40 °C, -24 °C) and thawing mode 11 (microwave or overnight at 4 °C) on instrumental textural profile analysis (ITPA) and cone penetration (CP) 12 parameters of mashed potatoes, the differences from freshly prepared product were less when the samples were 13 frozen at -80 °C and thawed by microwaving [1]. On the other hand, no difference was found in sensory 14 acceptability between samples frozen at -80 and -40 °C irrespective of whether thawing mode was used, which 15 reflects the panellists' did not find significant differences between air thawed vs. microwave thawed samples [1]. 16 Pretreatments can have a considerable effect, parti...